ref: bf8577992e69de9182d29fe37739dbd6b5ac7354
dir: /src_common/SKP_Silk_HP_variable_cutoff.c/
/*********************************************************************** Copyright (c) 2006-2011, Skype Limited. All rights reserved. Redistribution and use in source and binary forms, with or without modification, (subject to the limitations in the disclaimer below) are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of Skype Limited, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission. NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ***********************************************************************/ #include "SKP_Silk_main_FIX.h" #include "SKP_Silk_tuning_parameters.h" #define SKP_RADIANS_CONSTANT_Q19 1482 // 0.45f * 2.0f * 3.14159265359 / 1000 #define SKP_LOG2_VARIABLE_HP_MIN_FREQ_Q7 809 // log(80) in Q7 /* High-pass filter with cutoff frequency adaptation based on pitch lag statistics */ void SKP_Silk_HP_variable_cutoff( SKP_Silk_encoder_state *psEncC, /* I/O Encoder state */ SKP_int16 *out, /* O high-pass filtered output signal */ const SKP_int16 *in, /* I input signal */ const SKP_int frame_length /* I length of input */ ) { SKP_int quality_Q15; SKP_float pitch_freq_low_Hz; SKP_int32 B_Q28[ 3 ], A_Q28[ 2 ]; SKP_int32 Fc_Q19, r_Q28, r_Q22; SKP_int32 pitch_freq_Hz_Q16, pitch_freq_log_Q7, delta_freq_Q7; /*********************************************/ /* Estimate Low End of Pitch Frequency Range */ /*********************************************/ if( psEncC->prevSignalType == TYPE_VOICED ) { /* difference, in log domain */ pitch_freq_Hz_Q16 = SKP_DIV32_16( SKP_LSHIFT( SKP_MUL( psEncC->fs_kHz, 1000 ), 16 ), psEncC->prevLag ); pitch_freq_log_Q7 = SKP_Silk_lin2log( pitch_freq_Hz_Q16 ) - ( 16 << 7 ); //0x70 /* adjustment based on quality */ quality_Q15 = psEncC->input_quality_bands_Q15[ 0 ]; pitch_freq_log_Q7 = SKP_SUB32( pitch_freq_log_Q7, SKP_SMULWB( SKP_SMULWB( SKP_LSHIFT( quality_Q15, 2 ), quality_Q15 ), pitch_freq_log_Q7 - SKP_LOG2_VARIABLE_HP_MIN_FREQ_Q7 ) ); pitch_freq_log_Q7 = SKP_ADD32( pitch_freq_log_Q7, SKP_RSHIFT( SKP_FIX_CONST( 0.6, 15 ) - quality_Q15, 9 ) ); //delta_freq = pitch_freq_log - psEnc->variable_HP_smth1; delta_freq_Q7 = pitch_freq_log_Q7 - SKP_RSHIFT( psEncC->variable_HP_smth1_Q15, 8 ); if( delta_freq_Q7 < 0 ) { /* less smoothing for decreasing pitch frequency, to track something close to the minimum */ delta_freq_Q7 = SKP_MUL( delta_freq_Q7, 3 ); } /* limit delta, to reduce impact of outliers */ delta_freq_Q7 = SKP_LIMIT_32( delta_freq_Q7, -SKP_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ), SKP_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ) ); /* update smoother */ psEncC->variable_HP_smth1_Q15 = SKP_SMLAWB( psEncC->variable_HP_smth1_Q15, SKP_MUL( SKP_LSHIFT( psEncC->speech_activity_Q8, 1 ), delta_freq_Q7 ), SKP_FIX_CONST( VARIABLE_HP_SMTH_COEF1, 16 ) ); } /* second smoother */ psEncC->variable_HP_smth2_Q15 = SKP_SMLAWB( psEncC->variable_HP_smth2_Q15, psEncC->variable_HP_smth1_Q15 - psEncC->variable_HP_smth2_Q15, SKP_FIX_CONST( VARIABLE_HP_SMTH_COEF2, 16 ) ); /* convert from log scale to Hertz */ pitch_freq_low_Hz = SKP_Silk_log2lin( SKP_RSHIFT( psEncC->variable_HP_smth2_Q15, 8 ) ); /* limit frequency range */ pitch_freq_low_Hz = SKP_LIMIT_32( pitch_freq_low_Hz, SKP_FIX_CONST( VARIABLE_HP_MIN_FREQ, 0 ), SKP_FIX_CONST( VARIABLE_HP_MAX_FREQ, 0 ) ); /********************************/ /* Compute Filter Coefficients */ /********************************/ /* compute cut-off frequency, in radians */ //Fc_num = (SKP_float)( 0.45f * 2.0f * 3.14159265359 * pitch_freq_low_Hz ); //Fc_denom = (SKP_float)( 1e3f * psEncC->fs_kHz ); SKP_assert( pitch_freq_low_Hz <= SKP_int32_MAX / SKP_RADIANS_CONSTANT_Q19 ); Fc_Q19 = SKP_DIV32_16( SKP_SMULBB( SKP_RADIANS_CONSTANT_Q19, pitch_freq_low_Hz ), psEncC->fs_kHz ); // range: 3704 - 27787, 11-15 bits SKP_assert( Fc_Q19 >= 3704 ); SKP_assert( Fc_Q19 <= 27787 ); r_Q28 = SKP_FIX_CONST( 1.0, 28 ) - SKP_MUL( SKP_FIX_CONST( 0.92, 9 ), Fc_Q19 ); SKP_assert( r_Q28 >= 255347779 ); SKP_assert( r_Q28 <= 266690872 ); /* b = r * [ 1; -2; 1 ]; */ /* a = [ 1; -2 * r * ( 1 - 0.5 * Fc^2 ); r^2 ]; */ B_Q28[ 0 ] = r_Q28; B_Q28[ 1 ] = SKP_LSHIFT( -r_Q28, 1 ); B_Q28[ 2 ] = r_Q28; // -r * ( 2 - Fc * Fc ); r_Q22 = SKP_RSHIFT( r_Q28, 6 ); A_Q28[ 0 ] = SKP_SMULWW( r_Q22, SKP_SMULWW( Fc_Q19, Fc_Q19 ) - SKP_FIX_CONST( 2.0, 22 ) ); A_Q28[ 1 ] = SKP_SMULWW( r_Q22, r_Q22 ); /********************************/ /* High-Pass Filter */ /********************************/ SKP_Silk_biquad_alt( in, B_Q28, A_Q28, psEncC->In_HP_State, out, frame_length ); }